Bearing housing incorporating antimicrobial agent

ABSTRACT

A molded polymeric bearing housing is formed of a moldable polymer base material in combination with a glass fiber reinforcing component. A foaming agent is added to the base material to create a fine structural foam within interior regions of the housing. A density gradient is established between regions adjacent to the surfaces of the housing and the internal regions, thereby reducing the need for reinforcing ribs particularly in a base or mounting portion of the housing. An antimicrobial agent may be added to the housing material to inhibit the growth and proliferation of fungi, molds, bacteria, and so forth. Structural features of the housing may be formed subsequent to the molding process, such as by turning operations. Metal inserts may be provided to avoid crushing of regions of the housing, such as by attachment fasteners. The housing forms a mounting base surface in a single plane coextensive with the footprint of the housing. When the housing is placed in service moisture and debris is prevented from collecting below the housing by conformity of the mounting base surface with the machine support surface. The housing may be formed in a variety of styles, including pillow block styles, tapped base pillow block styles, two and four bolt flange styles, take up frame styles, flange bracket styles and so forth.

BACKGROUND OF THE INVENTION

[0001] 2. Field of the Invention

[0002] The present invention relates generally to the field ofantifriction bearings and housings for such bearings. More particularly,the invention relates to a molded polymeric bearing housing includingfeatures advantageous in certain applications, such as in the food andbeverage industries.

[0003] 2. Description of the Related Art

[0004] A wide range of applications exist for antifriction bearings,such as ball bearings, roller bearings, needle bearings and the like. Inmany industrial and material handling systems, such bearings perform afundamental function of permitting rotating machine elements to turnwith little resistance and thereby to effectively transmit power andmotion between drive system components. Applications for such bearingsinclude conveyors, mixers, pump drives, and the like, to mention just afew.

[0005] In general, bearings of the type commonly used in most industriesinclude an inner race, an outer race, and a plurality of anti frictionbearing elements disposed therebetween. The bearing elements arecaptured by the races and permit the races to rotate freely with respectto one another. The bearing assembly is typically installed in andsupported by a housing. A number of housing types are known and are incommon usage, including pillow block styles, two and four bolt flangedstyles, take-up frame styles, and so forth. In addition to supportingthe bearing inserts, such housings include features that permit them tobe easily attached to machine frames and other support structures at theapplication. Depending upon the housing style, these features typicallyinclude support feet or flanges traversed by apertures for receivingfasteners. Once mounted on the machine frame, a base surface of thebearing housing generally abuts the machine frame and forms a solidfoundation for both the bearing insert and for the machine elements heldin rotation by the bearing insert.

[0006] Housings of the type described above are commonly made of avariety of materials depending upon the particular application, theloads to which the bearing insert will be subjected and theenvironmental conditions of the application. For example, in mostbearing styles, metal housings provide sufficient mechanical support andresistance to loads. However, such metal housings are not well-suited tocertain applications. Specifically, in certain industries health orenvironmental constraints may make the use of metal bearing housingsdifficult or impossible. In the food and beverage industries, forexample, health requirements often necessitate frequent washing ofprocessing and material handling equipment including bearings and theirhousings. Under such conditions, conventional metal housings may tend tocorrode or otherwise degrade in ways that would contaminate the workingconditions of the machinery and/or the product processed by themachinery. Similarly, in chemical processing industries and certainmarine applications the presence of corrosive substances maysignificantly reduce the life of conventional metal bearing housings. Inresponse, the industry has began to employ alternative materials forbearing housings, including certain plastics.

[0007] In general, conventional plastic bearing housings are availablein the same styles as their metal counterparts. Thus, pillow blockbearing styles are available from various manufacturers which differonly slightly from designs available in metal. However, due tomanufacturing and processing constraints unique to plastic materialscertain features of conventional plastic bearing housings presentdrawbacks which make them unsatisfactory in specific industrialapplications. For example, due to the particular geometry of somebearing housing styles, such as pillow block housings, large volumes ofthe housing may be present in regions of the housing, while relativelythin or small volumes are present in other regions. Due to theexigencies of conventional injection molding processes, mostconventional designs therefore include ribbed structures in the largervolumes regions to provide the requisite structural integrity, whileproviding sufficient material flow and curing in those regions andavoiding drawing during the curing process. In pillow block designs, forexample, ribs are commonly provided below the bearing support and thelower support flanges. Some or all of these ribs contact the machineframe when the housing is installed, leaving voids or cavities below thebearing housing between the housing and the machine frame. While theplastic housing itself may perform adequately under frequent andrepeated washdowns, such interstices left between the housing and themachine frame tend to remain wet or moist. Over time, these areas tendto promote the growth of fungi, molds, bacteria and other microorganismsreducing the utility of the housing and requiring additional downtimefor cleaning or even replacement of the housing.

[0008] Industry responses to these problems have been less thansatisfactory. For example, one response has been to fill the voids orinterstices at the base of the bearing housing prior to placing thehousing in service. In one known approach, the entire base of thehousing is overmolded with an elastomeric or thermoplastic elastomerfiller in an attempt to cover the voids and cavities. However, thissolution provides a product which is non-uniform in appearance, andwhich requires additional tooling and manufacturing processes, adding tothe cost of the final product.

[0009] There is a need, therefore, for an improved polymeric bearinghousing which does not suffer from the drawbacks described above. Inparticular, there is a need for a bearing housing which can be used inapplications where environmental or health conditions require superiorresistance to corrosion, while inhibiting the proliferation ofmicroorganisms.

SUMMARY OF THE INVENTION

[0010] The invention provides an innovative polymeric bearing housingand a method for making such a housing designed to respond to theseneeds. The housing may be constructed in a variety of conventionalstyles, including pillow blocks, tapped base pillow blocks, two and fourbolt flanged models, take-up frame models, and so forth. All of themodels are molded from a polymeric material which can be properlyformulated to provide the requisite mechanical integrity, whileproviding features inhibiting growth of microbes. Specifically, in apreferred embodiment an admixture of the polymeric material and anantimicrobial agent is formed prior to molding. The resulting structurethereby inherently inhibits the proliferation of microbes on and aboutthe bearing housing. In accordance with another preferred embodiment, afoaming agent is added to the polymeric material to create a moldedstructure having varying densities throughout. Specifically, regions ofhigher density are formed near surfaces of the housing, while structuralfoam regions comprise the interior of the housing. Conventionalstructural ribs in a lower portion of the housing are thereby madeunnecessary. The housing therefore includes a substantially planarsupport base which can be mounted on a machine frame with substantiallyno interstices between the housing and the machine frame.

[0011] In a preferred embodiment, the base material from which thebearing housing is made has a light or white color to provide strongcontrast with potentially contaminating substances, such as in food andbeverage applications. Moreover, for such applications the basepolymeric material and the other components added to the material allpreferably comply with U.S. Food and Drug Administration standards,making the housing suitable for use on and around food, beverage,pharmaceutical and similar products.

[0012] Thus, in accordance with the first aspect of the invention, abearing housing comprises a unitary body made of a moldable polymericmaterial. The body includes a bearing insert support portion configuredto receive and support the bearing insert. The body also includes asupport base configured to receive and cooperate with fasteners tosecure the bearing housing to a substantially planar machine surface.The support base has a mounting surface extending substantially in aplane. Thus, the housing may be installed on a planar machine frame withno interstices formed between the body and the frame where moisture orother debris or fluids can collect.

[0013] In accordance with another aspect of the invention, a supporthousing is provided for a bearing insert of the type including an innerrace, an outer race, and an plurality of bearing elements disposedtherebetween. A support housing comprises a bearing insert supportportion and an attachment portion. The bearing insert support portion isconfigured to receive and support the bearing insert. The attachmentportion is formed integral with the bearing insert support portion andincludes a plurality of apertures configured to receive fasteners forsecuring the support housing to a machine support surface. The bearinginsert support portion and the attachment portion both comprise anantimicrobial agent or component for inhibiting growth ofmicroorganisms. In a particularly advantageous arrangement, the bearinginsert support portion and the attachment portion are made of anadmixture of a moldable polymeric material and the antimicrobial agent.

[0014] In accordance with another aspect of the invention, a method isprovided for manufacturing a housing for a bearing insert. The housingcomprises a bearing insert support portion configured to receive andsupport the bearing insert, and a mounting portion integral with thebearing insert support portion and configured for securing the housingto a machine frame. In accordance with the method, an admixture of amoldable polymeric material and an antimicrobial agent is formed. Theadmixture is injected into a mold to integrally form the bearing insertsupport portion and the attachment portion. The housing is then allowedto partially or completely cure and is removed from the mold. In apreferred embodiment, temperatures of surfaces of the mold arecontrolled during the molding and curing steps to form a substantiallyclosed skin on the housing.

[0015] In another preferred method for manufacturing a bearing housing,an admixture of a moldable polymeric material and a foaming agent isformed. The admixture is injected into a mold to integrally form thesupport portion and the mounting portion of the bearing housing. Aparameter of the mold is controlled to form boundary regions adjacent tosurfaces of the housing, and internal regions. The boundary regions havea somewhat higher density than the internal regions. The housing is thenat least partially cured and subsequently removed from the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The foregoing and other advantages of the invention will becomeapparent upon reading the following detailed description and uponreference to the drawings in which:

[0017]FIG. 1 is a perspective view of a pillow block style bearinghousing in accordance with certain aspects of the invention;

[0018]FIG. 2 is a sectional view of the bearing housing illustrated inFIG. 1 along line 2-2;

[0019]FIG. 3 is a sectional view of the housing illustrated in FIG. 1along line 3-3;

[0020]FIG. 4 is a perspective view of a tapped base pillow block stylebearing housing in accordance with certain aspects of the invention;

[0021]FIG. 5 is a sectional view of the bearing housing illustrated inFIG. 4 along line 5-5;

[0022]FIG. 6 is a sectional view of the bearing housing illustrated inFIG. 4 along line 6-6;

[0023]FIG. 7 is a perspective view of a further alternativeconfiguration wherein the bearing housing is formed as a four-boltflanged arrangement;

[0024]FIG. 8 is a sectional view of the bearing housing of FIG. 7 alongline 8-8;

[0025]FIG. 9 is a detailed view of a portion of a bearing housing inaccordance with certain aspects of the invention illustrating relativedensities of a structural foam material of which the housing isconstructed in accordance with a preferred embodiment; and

[0026]FIG. 10 is a flow chart illustrating exemplary manufacturingprocess steps in a preferred method for manufacturing a bearing housingin accordance with the invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0027] Turning now to the drawings and referring first to FIG. 1, abearing housing, designated generally by reference numeral 10, isillustrated as supported on a machine frame 12. In the embodimentillustrated in FIG. 1, bearing housing 10 is a flange mounted pillowblock style having a central region 14 flanked by lateral mountingflanges 16 and 18. A central aperture 20 is formed in central region 14.An internal bearing support surface 22 bounds aperture 20 for supportinga bearing insert 24 (illustrated in broken lines in FIG. 1). It shouldbe noted that the particular embodiment illustrated in FIG. 1 as well asalternative embodiments discussed below may be configured for supportingvarious types of bearing inserts of known configuration. In particular,housing 10 may be employed for supporting straight roller bearings,tapered roller bearings, ball bearings, needle bearings, sleeve bearingsand so forth.

[0028] Each lateral mounting flange 16 and 18 includes mountingapertures 26 for receiving fasteners 28. Fasteners 28, typicallythreaded bolts, extend through apertures 26 when bearing housing 10 isinstalled, and into threaded bores (see FIG. 3) in machine frame 12. Aswill be appreciated by those skilled in the art, various securingarrangements may be utilized in place of threaded bores and fasteners28, such as nut and bolt sets, and the like. In the presently preferredembodiment, support sleeves 30 are disposed within each mountingaperture to provide additional resistance of the mounting flanges toforces exerted by fasteners 28, thereby resisting crushing of theflanges. Sleeves 30 are preferably preformed of metal, such as stainlesssteel, and secured within mounting apertures 26 during molding ofhousing 10 as discussed in greater detail below.

[0029] Central region 14 of housing 10 preferably includes upper facetedsurfaces 32. A lubrication fitting 34 is threaded into one of thefaceted surfaces to provide a lubrication path for bearing insert 24 asdiscussed below. Housing 10 further includes a substantially planar orflat mounting base 36 extending over its entire footprint. Thus,mounting base 36 lies substantially in a single plane beneath bothlateral mounting flanges 16 and 18 and central region 14. This preferredconfiguration of housing 10 is particularly well suited for mounting ona machine frame 12 having a substantially planar support surface 38. Asdiscussed in greater detail below, the use of an integral uniplanarmounting base 36 permits housing 10 to be mounted on planar surface 38with no entrapped voids or volumes therebetween, reducing the potentialfor collecting moisture, debris and other substances beneath housing 10.

[0030] As best shown in FIG. 2, in the illustrated embodiment housing 10has a front side 40 and a rear side 42, front side 40 being configuredto facilitate insertion of a bearing insert into housing 10. Thus, frontside 40 includes an entry chamfer 44 and a pair of lateral recesses 46(see FIG. 3) at the approximate vertical midpoint of bearing supportsurface 22. Bearing support surface 22 comprises a spherical groove 48formed around the entire annulus of central aperture 20. A pair of sealgrooves 50 are provided on either side spherical groove 48. Theforegoing structure permits a bearing insert having a spherical outerring to be positioned and locked into housing 10 in a manner similar tothat employed in conventional bearing housings. Moreover, once thebearing insert is positioned within housing 10, one or more bearingseals of generally known design may be secured in grooves 50 to inhibitthe ingress of moisture and debris into housing 10. In the illustratedembodiment, housing 10 is bilaterally symmetrical permitting a cover(not shown) to be mounted over either front side 40 or rear side 42 asdesired in particular applications.

[0031]FIG. 3 shows the foregoing structures in a transverse section ofhousing 10. As illustrated in FIG. 3, central region 14 is formedintegrally with lateral mounting flanges 16 and 18. Moreover, supportsleeves 30 extend substantially over the entire height of flanges 16 and18 and terminate in surfaces generally flush with the upper and lowerextremities of apertures 26. Once tightened in place, fasteners 28 thusbear upon sleeves 30 to securely hold housing 10 in its desired positionon machine frame 12. As noted above, once secured in position, planarmounting base 36 of housing 10 conforms to planar surface 38 of machineframe 12, over substantially the entire footprint of flanges 16 and 18and central region 14.

[0032] In the preferred embodiment illustrated, central region 14 andflanges 16 and 18 are injection molded from a polymeric material. In thepresently preferred embodiment, housing 10 is formed ofpolybutyleneterephthalate (PBT) in combination with a reinforcing glassfiber. PBT is available from numerous commercial sources, such asDSM-Engineering Plastics of Evansville, Ind. under the commercialdesignation Arnite®. The particular resin utilized preferably complieswith U.S. Food and Drug Administration Standards for use in food andbeverage industries, such as those found in 21 C.F.R. 177.1660.Moreover, the resins utilized for housing 10 may include pigmentscomplying standards promulgated in 21 C.F.R. 178.3297. To facilitate theformation of planar mounting base 36 coextensive with the footprint ofhousing 10, the polymeric material of which housing 10 is formedpreferably constitutes a structural foam material formed by endothermicchemical nucleating and foaming agents added to the polymeric materialprior to injection molding. An acceptable foaming agent for the PBTmaterial presently preferred is commercially available from BI Chemical,Specialty Products Division, Winchester, Va. under the commercialdesignation Hydrocerol CF 40. As will be appreciated by those skilled inthe art, such foaming agents may be added to the polymeric materialprior to injection molding to induce direct gassing to form a very finecell foam.

[0033] It has been found that the use of a structural foam for housing10 permits the formation of relatively large volumes in certain regionsof housing 10 in combination with relatively thin structures in otherregions while resisting material drawing. Specifically, boundary regions52 may be formed adjacent to external surfaces 54 of housing 10 whileinternal regions 56 extend therebetween. Such boundary regions are ofrelatively higher density than internal regions 56. Moreover, thecombination of the polymeric base material with the foaming agent formsa generally closed skin over the entire external surface 54 of housing10. As best illustrated in FIG. 9, a density gradient is thereforedefined between boundary regions 52 lying closely adjacent to externalsurface 54 and internal regions 56 lying within the larger volumes ofhousing 10. In the presently preferred embodiment, density variations ofsome 5 to 10 percent have been found to stabilize between externalsurface 54 and internal regions 56. As will be appreciated by thoseskilled in the art, the particular density gradient locations and thedensity variations extending through the gradients will vary with thelocal geometry of the housing, with larger volume sections having lowerdensity internal regions than thinner or lower volume sections.

[0034] In addition to fiber reinforcing components and a foaming agent,in the presently preferred embodiment, housing 10 includes anantimicrobial agent additive for inhibiting the growth and proliferationof bacteria, fungi, microorganisms and the like. As used herein, theterms “microorganisms” and “antimicrobial agent” are intended to refergenerally to all such plant and microbial forms. As will be appreciatedby those skilled in the art, such antimicrobial agents may be added tothe polymeric material prior to injection molding and remain effectivefollowing the molding process. An acceptable antimicrobial agent iscommercially available from Thompson Research Associates of Toronto,Ontario, Canada under the commercial designation Ultra-Fresh®.

[0035] In the presently preferred embodiment, most external surfaces 54of housing 10 are formed during the molding process. Specifically,mounting apertures 26 are formed around support sleeves 30 which areinserted into the mold cavity prior to injection of the polymericmaterial. Moreover, a short lubricant channel 58 is preferably formedthrough an upper portion of the housing by means of a suitable core pin.Lubricant channel 58 extends from one of faceted surfaces 32 through anupper portion of central region 14 to bearing support surface 22. Toaccommodate lubricant fitting 44, a threaded sleeve 60 is provided inchannel 58. Sleeve 60 is preferably held by the core pin used to formchannel 58 during the molding process, thereby embedding sleeve 60 intohousing 10 during the molding process. As illustrated, sleeve 60includes a grooved outer profile to reduce the risk of pullout onceembedded into housing 10. It should be noted that this preferredstructure facilitates conversion of housing 10 to a permanentlylubricated bearing housing by elimination of the core used to formchannel 58 and to embed sleeve 60. Moreover, the use of faceted upperfaces 32 allows the core to be eliminated while avoiding the creation ofa cosmetic blemish in the previous location of the core.

[0036] Internal features of bearing support surface 22 are preferablyformed by machining operations subsequent to removal of housing 10 fromits mold. Thus, spherical groove 48 and seal grooves 50 are preferablyformed by turning operations. This preferred methodology both reducestooling costs for the injection molding process and facilitates specialconfigurations of housing 10 via the subsequent machining operations.

[0037] As mentioned above, the innovative features of the presentbearing housing design may be incorporated in various housing styles.FIGS. 4 through 6 illustrate a tapped base pillow block housingconstructed in accordance with the features described above. The tappedbase pillow block housing illustrated, designated generally by thereference numeral 62, includes an upper central portion 64 from whichlateral supports 66 extend. Bolt apertures 68 are formed in each lateralsupport 66, as illustrated in FIG. 5. Tapped sleeves 70, preferably madeof stainless steel, are provided within each bolt aperture 68 forreceiving and interfacing with threaded fasteners 28. In the illustratedembodiment, sleeves 70 have a grooved profile to resist pullout.Portions of the profile may be faceted (e.g. hexagonal) to resisttwisting within the housing under the influence of fasteners 28. Eachsleeve is preferably inserted by means of a core provided in the moldused to form housing 62. As discussed above with respect to housing 10,housing 62 is preferably formed of a polymeric material such as PBT andincludes a glass fiber reinforcing component. Moreover, in the preferredembodiment a planar mounting base 36 is formed on housing 62 such thathousing 62 may be mounted directly on a planar mounting surface 38 of amachine frame with no interstice therebetween. To facilitate formationof planar mounting base 36, a foaming agent is added to the polymericmaterial used to mold housing 62, creating boundary regions 52 betweenwhich internal regions 56 of lower density stabilize as discussed above.In the embodiment illustrated in FIGS. 4 through 5, features of themolded housing are formed via subsequent machining operations, such asspherical bearing support group 48 (see FIG. 6) and seal grooves 50 oneither side of spherical groove 48.

[0038]FIGS. 7 and 8 illustrate a four bolt flanged bearing housingincorporating the innovative features described above. Thus, as shown inFIG. 7, a four bolt flanged housing 72 includes a raised central portion74 surrounded by a peripheral flange 76. A central aperture 20 is formedin central portion 74 and a bearing support surface 22 surrounds centralaperture 20 as described above with reference to housings 10 and 62.Raised fastener supports 78 are formed in each corner of flange 76 forreceiving fasteners used to secure housing 72 to a planar machinesupport surface. Support sleeves 80, preferably formed of stainlesssteel, are lodged within each fastener support 78 to interface withfasteners and to prevent crushing of fastener supports 78. Asillustrated in FIG. 8, a lubrication channel 58 is formed in centralportion 74 and a lubrication fitting sleeve 60 is lodged within channel58 for receiving a lubrication fitting as described above. Lubricationchannel 58 communicates with bearing support surface 22, andspecifically with spherical groove 48. As in the previous embodiments,housing 72 is formed of a polymeric base material including a glassfiber reinforcing component. A foaming agent is added to the materialprior to molding to create a structural foam in internal regions asdesignated by reference numeral 56. Also as in the previous embodiments,a planar mounting base 36 is formed which directly contacts a planarmounting surface 38 of a machine frame when housing 72 is placed inservice. It should be noted that due to the annular configuration ofhousing 72, the footprint of planar mounting base 36 is similarlyannular. As in the previous embodiments, certain features of housing 72are preferably formed by subsequent machining operations following themolding process. Specifically, spherical groove 48 and a seal groove 50are formed by turning operations.

[0039] As mentioned above, the housings of the present invention areformed by a sequence of operations including a molding process in whicha specific polymeric formulation is created to lend favorable propertiesto the housings in their final form. FIG. 10 illustrates exemplary stepsin the manufacturing process used to form the housings. Prior to thespecific manufacturing steps enumerated in FIG. 10, a suitable mold isformed in accordance with generally known techniques. Specifically, ithas been found that the desired shapes can be created in a two-part moldin which retractable cores are utilized to form the cavities andapertures described above. Moreover, as will be appreciated by thoseskilled in the art, cooling coils are provided adjacent to mold cavitysurfaces in order to afford temperature control during the curing of thehousings. Such temperature control is desirable to create a generallyclosed skin over the entire exterior surface of the housings and tomodulate the formation of density gradients in the structural foammaterial.

[0040] The manufacturing process, designated generally by referencenumeral 100 in FIG. 10, begins with opening the mold cavity as indicatedat step 102. Sleeves to be included in the final housing are theninserted into the mold cavity as indicated at step 104, being held inplace by suitable cores or internal protrusions formed in the cavity.The specific sleeves utilized and their locations will vary dependingupon the housing type, but will generally include stainless steelsleeves within each fastener aperture and a lubrication fitting sleevefor lubricated bearings. Moreover, in the illustrated embodiments, coresare provided for forming both the central aperture in the housings aswell as the mounting fastener apertures and the lubricant channel asdescribed above.

[0041] The desired admixture of the base polymeric material and otheragents is prepared as indicated at steps 106 through 112. If the basepolymeric material does not already include a glass fiber reinforcingcomponent, this component is added as indicated at step 106. At step108, a foaming agent is added to the admixture to provide the gassingdesired for creation of the structural foam as described above. Asindicated at step 110, an antimicrobial agent is then added to theadmixture of polymer, glass fiber reinforcing material and foamingagent. Where a thermoplastic base material is utilized, such as PBT, thepolymer admixture is preheated as indicated at step 112. It should benoted that the foregoing steps may occur in various orders dependingupon the specific materials utilized and their initial and desiredforms. For example, in specific applications where an antimicrobialagent is not to be used, such as in certain chemical processingapplications, step 110 may be eliminated. Similarly, in certainapplications calling for the use of an antimicrobial agent in anon-structural foam product, the addition of foaming agent may bedispensed with.

[0042] At step 114, the admixture is injected into the mold cavity, andat step 116 the internal surfaces of the mold cavity are cooled topromote the creation of a density gradient in the housing, particularlythrough larger volume regions. The housing is then allowed at leastpartially to cure as indicated at step 118 and, following the cureperiod, the mold is opened and the housing is removed as indicated atstep 120. In the present embodiment, the molded body is permitted topartially cure in the mold and subsequently to air cure followingremoval from the mold. Where final features of the housing are still inneed of definition, as in the preferred embodiment, final machiningoperations are performed on the housing blank as shown at step 122.Specifically, internal grooves and similar features may be convenientlyformed by such machining operations, reducing the need for specialcores.

[0043] While the invention may be susceptible to various modificationsand alternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

What is claimed is:
 1. A housing for a bearing insert, the housingcomprising: a unitary body made of a moldable polymeric material andhaving a bearing insert support portion configured to receive andsupport the bearing insert, and a support base configured to receive andcooperate with fasteners to secure the housing to a substantially planarmachine surface, the support base having a mounting surface extendingsubstantially in a plane.
 2. The housing of claim 1, wherein the body ismade of a moldable structural foam material.
 3. The housing of claim 1,wherein the polymeric material includes an antimicrobial agent forinhibiting growth of microorganisms.
 4. The housing of claim 1, whereinthe body is made of a composition including a moldable plastic material,fiberglass, and an antimicrobial agent.
 5. The housing of claim 1,wherein the support base includes a central portion underlying thebearing support portion and a pair of lateral flanges extending from thecentral portion, the mounting surface comprising a region coextensivewith the lateral flanges and the central portion.
 6. The housing ofclaim 1, wherein the polymeric material comprises polybutyleneterephthalate.
 7. A support housing for a bearing insert, the bearinginsert including an inner race, an outer race and a plurality of bearingelements disposed therebetween, the support housing comprising: abearing insert support portion configured to receive and support thebearing insert; and an attachment portion integral with the bearinginsert support portion, the attachment portion including a plurality ofapertures configured to receive fasteners for securing the supporthousing to a machine support surface; wherein the bearing insert supportportion and the attachment portion comprise an antimicrobial agent forinhibiting growth of microorganisms.
 8. The support housing of claim 7,wherein the bearing insert support portion and the attachment portionare made of an admixture of a moldable polymeric material and theantimicrobial agent.
 9. The support housing of claim 8, wherein theadmixture further includes a fiberglass reinforcing component.
 10. Thesupport housing of claim 8, wherein the moldable polymeric materialcomprises a structural foam.
 11. The support housing of claim 7, whereinthe attachment portion forms a base on which the support housing ismounted when placed in service, and wherein the base includes a basemounting surface extending substantially in a plane and coextensive withthe base.
 12. A housing for supporting a bearing insert on asubstantially planar machine frame, the bearing insert including aninner race, an outer race and a plurality of bearing elements disposedtherebetween, the housing comprising: a molded, polymeric bearing insertsupport portion configured to receive and support the bearing insert;and a molded, polymeric mounting portion integral with the bearinginsert support portion, the mounting portion having a substantiallyplanar mounting surface extending substantially over the entire mountingportion, whereby when the housing mounted on the machine frame, themounting surface contacts the machine frame with no intersticetherebetween; wherein the bearing insert support portion and themounting portion comprise a structural polymeric foam material.
 13. Thehousing of claim 12, wherein the bearing insert support portion and themounting portion comprise an admixture of a moldable polymeric materialand an antimicrobial agent for inhibiting growth of microorganisms. 14.The housing of claim 12, wherein the mounting portion includes aplurality of apertures extending through the mounting surface, theapertures being configured to receive fasteners for securing the housingto the machine frame.
 15. The housing of claim 12, wherein the mountingportion includes a plurality of mounting apertures for securing thehousing to a machine frame, and wherein a metallic support sleeve isdisposed within each of the plurality of mounting apertures.
 16. Thehousing of claim 15, wherein the bearing insert support portion and themounting portion comprise an admixture of the polymeric structural foammaterial and a fiberglass reinforcing component.
 17. A method formanufacturing a housing for a bearing insert, the housing comprisingbearing insert support portion configured to receive and support thebearing insert, and a mounting portion integral with the bearing insertsupport portion and configured for securing the housing to a machineframe, the method comprising the steps of: (a) forming an admixture of amoldable polymeric material and an antimicrobial agent; (b) injectingthe admixture into a mold to integrally form the bearing insert supportportion and the attachment portion; (c) curing the housing; and (d)removing the housing from the mold.
 18. The method of claim 17,comprising the further step of foaming the admixture prior to injectingthe admixture into the mold.
 19. The method of claim 18, comprising thefurther step of controlling temperatures of surfaces in the mold to forma substantially closed skin on the housing.
 20. The method of claim 17,comprising the further step of adding a fiberglass reinforcing componentto the admixture prior to injecting the admixture into the mold.
 21. Themethod of claim 17 wherein the mold is configured to form asubstantially planar mounting base on the mounting portion.
 22. A methodfor manufacturing a bearing housing, the housing having a bearing insertsupport portion and a mounting portion integral with the bearing insertsupport portion, the method comprising the steps of: (a) forming anadmixture of a moldable polymeric material and a foaming agent; (b)injecting the admixture into a mold to integrally form the supportportion and the mounting portion; (c) controlling a parameter of themold to form boundary regions having a first densities adjacent tosurfaces of the housing and an internal regions having second densitiesbetween the boundary regions, the first densities being greater than thesecond densities; (d) curing the housing; and (e) removing the housingfrom the mold.
 23. The method of claim 22, comprising the further stepof adding an antimicrobial agent to the moldable polymeric material. 24.The method of claim 22, wherein the mounting portion includes aplurality of mounting apertures, and wherein the method comprises thefarther step of inserting a plurality of metallic sleeves into the moldprior to injection of the admixture, such that each of the metallicsleeves is disposed in a corresponding mounting aperture in thecompleted housing.
 25. The method of claim 22, wherein the mountingportion is formed with a substantially flat mounting surface, wherebythe housing may be mounted on a planar machine frame with no intersticetherebetween.